This invention relates to an emergency stretcher which can be loaded into an emergency vehicle and, more particularly, to such an emergency stretcher with castor wheels.
Emergency stretchers (also known as ambulance stretchers or cots) are specialized stretchers usually used in association with emergency vehicles. The ambulance stretcher is specialized due to it being capable of easy loading into the emergency vehicle. More specifically, the wheeled base and patient support structure are collapsible as the stretcher is moved into the inside of the emergency vehicle to facilitate ambulance personnel to work on the patient lying on the stretcher in the fairly limited space inside the emergency vehicle. Although preexisting ambulance stretchers are generally adequate for their intended purposes, they have not been satisfactory in all respects.
Stretchers are typically provided with wheels at the lower end of the support structure. The front pair of wheels rotate about a fixed axis to allow the stretcher to move in its longitudinal direction. An example of such wheels can be found in U.S. Pat. No. 5,015,024. While this wheel structure is adequate for longitudinal movement of the stretcher, it is inadequate for nonlongitudinal movement of the stretcher. Accordingly, it is desirable to provide a stretcher that has selectively pivotal castors on the front legs.
German Utility Model No. 295 17 605 shows another type of wheeled base that has selectively pivotal castors on a leg. A castor rotation device is provided to positively swivel the castors when the legs are collapsed by action of a screw type height control mechanism. A swivel blocking pin is mounted outside the leg. The blocking pin engages the castor to selectively prevent swiveling of the castor about the leg. A cable for controlling the pin is also provided outside the leg. However, for the castor rotation device to work the block pin must first be released from engagement with the castor. This adds an extra step during insertion of this stretcher into an emergency vehicle. Moreover, it is time consuming to collapse the legs using this screw type height control mechanism.
British Patent No. 1 168 319 shows a castor with both a rotational lock and a swivel lock. Both locks are provided on the castor at an end of a leg. This is a significant drawback in ambulance stretchers. It may be difficult to reach the castors with a person""s foot. Moreover, the locks must be individually actuated to lock both legs.
U.S. Pat. No. 4,921,295 shows an ambulance stretcher having a track with two downwardly open channels that receive slide members. The legs are connected to the slide members. The legs pivot in response to movement of the slide members in the channels. The slide members are bearingless and metal. The track is metal. Oil lubricates the track so that the slide members can slide in the channels. There are some drawbacks associated with this arrangement. First, the structure requires lubrication. The lubricant can escape through the downward openings in the channels. Second, grit and other debris may enter the openings in the channels and be held by the lubricant. The grit may come into contact between the slide members and tracks causing excessive wear. Third, if either the slide member or track becomes worn or damaged, then that entire part must be replaced. Fourth, the channel is enclosed over about 270 degrees and only contacts the slide member over approximately 210 degrees. Thus, spaces are created between the slide member and the track. Fifth, due to the need for lubrication and the spaces between the slide member and channel, this stretcher should not be power washed. Power washing removes the lubricant and water will become trapped in the spaces between the slide member and channel.
The present invention provides castors so that the stretcher can operate in a castor mode to easily steer the stretcher. The castor mode allows the castors to swivel 360 degrees around the leg. The stretcher can also operate in a fixed mode to fix the castors in one direction so that the stretcher travels in the longitudinal direction. That is, the fixed mode prevents swiveling of the castors.
The present invention provides a castor lock control assembly that allows medical personnel to easily select the operating mode of the castors. The control assembly is accessible from both sides of the stretcher to lock or release the castors. Consequently, personnel need not be located at only one side of the stretcher to access the control assembly to select the mode of operation of the stretcher.
The control assembly of the present invention positively locks the castors in either a swivel state or in a fixed orientation. This improves the safety of the stretcher to prevent unintended release or lock of the castors.
The present invention houses the swivel lock mechanism in the leg. This prevents accidental operation of the swivel lock mechanism and improves its durability.
The present invention provides an auxiliary handle structure which has an extended position and a folded position relative to a stretcher base. The auxiliary handle structure, in the extended position, allows the height of the base to be adjusted. In the folded position, the auxiliary handle structure can not adjust the height of base.
The present invention provides a wear bumper arrangement on the legs, which withstands rigorous contact with the emergency vehicle during insertion and removal of the stretcher. The arrangement is easily installed on legs. The arrangement also includes a wear roller that supports the legs on the emergency vehicle.
The present invention has a beam providing a track for slidable elements that are connected to the legs. The slidable elements have slide bushings which allow the elements to easily slide within channels in the track to raise/lower the height of the ambulance stretcher or collapse the legs for insertion into a vehicle. These bushings are replaceable. Bushings contact the channel to support the slide elements and perform a wiping function thereby cleaning the channel.